1. Field of the Invention
The present invention relates to a portable information processing terminal device such as PDA (Personal Digital(Data) Assistants) for example, and its file management method, with improvement for realizing both a low power consumption and a large memory capacity.
2. Description of the Background Art
In recent years, computers are becoming more compact and light due to the advance of the semiconductor technology, so that various handy portable information processing terminal devices have been developed as exemplified by PDA and palm-top PC. In such a compact portable information processing terminal, it has been customary to provide only a semiconductor memory as a secondary storage for storing files, without providing any large capacity memory device such as hard disk, due to limitations on its size, weight, continuously operable time using a battery, etc.
However, the number and size of files utilized by users are steadily increasing recently so much so that there are increasing demands for implementing a large capacity memory device such as hard disk on the portable information processing terminal in order to store these files.
But the hard disk has a very large power consumption because of its driving system including a motor and a head, even though its memory capacity is very large. For this reason, the portable information processing terminal that is often used in a battery driven mode will have a problem if the hard disk is implemented on it because the continuously operable time using a battery would be shortened considerably. On the other hand, if a large capacity battery is implemented in order to extend the continuously operable time using a battery, the size and weight of the terminal would be increased to such an extent as to hamper the portability of the terminal.
It is therefore an object of the present invention to provide a portable information processing terminal device and its file management method capable of providing a sufficient data memory capacity without hampering the portability by realizing both a low power consumption and a large memory capacity.
According to one aspect of the present invention there is provided an information processing terminal device, comprising: a first memory for storing files; a second memory for storing a plurality of files, the second memory having a larger memory capacity and a higher power consumption than the first memory; a processing unit configured to read and process files stored in the first memory, and to access the second memory when a desired file does not exist in the first memory; a judgement unit configured to judge whether there is a possibility of external power supply or not; a prohibition unit configured to prohibit activation of the second memory when the judging unit judges that there is no possibility of external power supply; and a control unit configured to select prescribed files that are expected to have probabilities for being accessed during a period in which activation of the second memory is prohibited by the prohibition unit, and to store the prescribed files into the first memory in advance.
According to another aspect of the present invention there is provided a file management method for managing files of an information processing terminal device having a first memory for storing files and a second memory for storing a plurality of files, the second memory having a larger memory capacity and a higher power consumption than the first memory, the file management method comprising the steps of: judging whether there is a possibility of external power supply or not; prohibiting activation of the second memory when the Judging step Judges that there is no possibility of external power supply; and selecting prescribed files that are expected to have probabilities for being accessed during a period in which activation of the second memory is prohibited by the prohibiting step, and storing the prescribed files into the first memory in advance.
According to another aspect of the present invention there is provided a computer usable medium having computer readable program codes embodied therein for causing a computer to function as a file management method for managing files of an information processing terminal device having a first memory for storing files and a second memory for storing a plurality of files, the second memory having a larger memory capacity and a higher power consumption than the first memory, the computer readable program codes include: a first computer readable program code for causing said computer to judge whether there is a possibility of external power supply or not; a second computer readable program code for causing said computer to prohibit activation of the second memory when the first computer readable program code Judges that there is no possibility of external power supply: and a third computer readable program code for causing said computer to select prescribed files that are expected to have probabilities for being accessed during a period in which activation of the second memory is prohibited by the second computer readable program code, and to store the prescribed files into the first memory in advance.